PM2.5 Exceedances in Zurich 2024
Annual monitoring data from NABEL stations in Zurich showing 23 days exceeding WHO PM2.5 guidelines, with peak events linked to Saharan dust and temperature inversions.
Provenance
Legal Citation
FOEN/EMPA. (2024). NABEL Air Quality Monitoring: Zurich Stations Annual Report 2024. Retrieved from https://opengovclimate.ch/en/evidence/pm25-monitoring-zurich/
Location
Measurement Period
The NABEL monitoring station Zurich-Kaserne recorded an annual mean PM2.5 concentration of 11.2 ug/m3 in 2024 — more than double the WHO guideline of 5 ug/m3. Twenty-three days exceeded the 24-hour WHO guideline of 15 ug/m3.
Key Findings
- Annual mean PM2.5: 11.2 ug/m3 (WHO guideline: 5 ug/m3)
- Exceedance days: 23 days above WHO 24-hour guideline
- Peak concentration: 68.4 ug/m3 (February 14, during Saharan dust event)
- Winter inversion events: 8 multi-day episodes with sustained PM2.5 above 25 ug/m3
Legal Significance
While Switzerland’s national PM2.5 limit (LRV Annex 7) of 10 ug/m3 annual mean was exceeded, the WHO guideline of 5 ug/m3 — increasingly cited in Swiss litigation — was exceeded by a factor of 2.2. Under USG Art. 11-13, authorities must take precautionary measures to reduce emissions.